Dosimetric evaluation of a benchtop kilovoltage X-ray irradiator for accurate and repeatable low-dose cell irradiation

The capability of a benchtop kilovoltage X-ray irradiator was evaluated for accurate and repeatable low-dose irradiation of cell cultures. Dose measurements were performed using the in-air method described in AAPM Task Group 61 guidelines at 40 kVp with tube currents of 0.1, 0.2, 0.4, and 0.7 mA, and a 0.5-mm Al filter. The measured half-value layer was 0.77 mm Al. Slope-based dose rates ranged from 0.006471 Gy/min (0.1 mA) to 0.05497 Gy/min (0.7 mA). A relative dose uncertainty of 2% was achieved for 30-s exposures, improving further with longer durations. Dose verification confirmed acceptable uncertainty (<±5%) for exposures of at least 22 s. Correction factors were derived to account for attenuation by the polystyrene T25 flask, ensuring accurate dose delivery. Dose uniformity analysis showed decrease in dose with increased distance from the center following the inverse square law, and asymmetry along horizontal axis due to the anode heel effect. The irradiator exhibited linear, stable, and repeatable dose delivery, with 40 kVp at 0.1 and 0.2 mA reliably producing doses as low as 0.01 Gy. Improved accuracy and precision were achieved with longer exposures. These findings highlight the influence of time-related effects in delivering the intended dose. Overall, the benchtop irradiator demonstrated suitability for controlled low-dose cellular irradiation, with turntable rotation recommended to enhance field uniformity in multi-flask setups. • The benchtop kilovoltage X-ray irradiator delivers precise doses down to 0.01 Gy with consistent linearity and repeatability. • Longer irradiation improves dose accuracy and repeatability. • Slope-based dose rates reliably represent values with minimal deviation while accounting for end effects. • Correction factors are essential to address dose discrepancies from material attenuation during flask irradiation.